Need help with box and ports

Making a ported box for my 2 (only have one right now) power hx2. here are my measurments so far.

14h x 36w x 18d = 5.25 ft3 am i right?

after displacement, we talking roughly 2.5 per sub right?\
No on to the ports, rockford give dimensions for the ports but i dont understand them.
here they are, keep in mine that they for 2.50 ft3 per sub.

they have a tuning frew for either 35, 40, or 45 hz which is better??
for the 35 it goes like this(will list that only, and if a dif is better, let me kno)

rockford's instuctions are pretty well incrypted they only want dealers working on their merchandise, but from glancing at your specs they look alright, but i would not actually know for 100% unless i saw the box and the way you are building it.i would go with 35 and if you really don't know what size ports to install go ask a shop they know everything...but take the box with you to avoid any confusion